JP5617651B2 - Communication device and control device - Google Patents

Description

  The present invention relates to a communication device that performs communication with a field device, and a control device including the device.

  Conventionally, in plants and factories, field devices called field devices (measuring instruments, operating devices) and control devices that control these devices have been connected via a communication bus in order to realize advanced automatic operations. A distributed control system (DCS) has been established. Also, based on this distributed control system, a safety instrument system (SIS: Safety Instrument System) that automatically maintains a plant or the like in a safe state even when an abnormality occurs has been constructed.

  In plants, etc., safety and reliability are given top priority. Therefore, control devices that control and control distributed control systems and safety instrumentation systems prevent erroneous data from being sent to field devices. The mechanism to do is adopted. Specifically, CPUs (central processing units) are made redundant, and detection of erroneous operations is made possible by collating the computation results of each CPU with a collator. In addition, an ECC (Error Check and Correct memory) memory capable of detecting and correcting errors is provided, and it is possible to detect and correct errors that occur when stored data are garbled or when data is read or written. For details of a conventional redundant processor device including a redundant microprocessor, see, for example, Patent Document 1 below.

JP 2001-256070 A

  By the way, the communication (IO communication) performed between the control device and the field device described above is roughly classified into arterial communication and venous communication. Arterial communication is communication for the purpose of exchanging control data to field devices such as PV (Process Value) and SV (Set Value). In contrast, vein communication is communication aimed at exchanging data for diagnosis and prevention of field devices.

  In recent years, venous communication has become important in order to ensure higher safety and reliability of plants and the like, and the amount of communication has increased to the same level as that of arterial communication. However, if the communication volume of venous communication increases, the load on the CPU provided in the control device increases, and there is a possibility that the original control calculation for generating control data for controlling the field device may be hindered. There's a problem.

  Here, it is considered that the above problem can be solved by separately providing a communication processor for performing vein communication and separating the communication packet generation processing and communication processing used in vein communication from the CPU. In addition, if only the processing for generating communication packets used in arterial communication is performed by the CPU and the communication processing of the communication packets is performed by the above-described communication processor, the processing capacity of the CPU is reduced to the original control calculation and communication. It can be distributed to packet generation processing. Then, for example, when there is a process with higher priority than the communication process (interrupt process or the like) for the CPU, it is considered that a problem such as a delay in the communication process of the communication packet can be avoided.

  The above-described vein communication does not change the IO communication performed between the control device and the field device, and therefore, the same reliability as the arterial communication is required. Control data (communication packet) communicated by arterial communication is generated and verified by a redundant CPU, and is stored in the ECC memory, so that reliability is ensured. However, since it is difficult from the viewpoint of cost to make the communication processor redundant, the reliability of the vein communication cannot be ensured by the same technique of the arterial communication.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication device capable of realizing highly reliable communication without significant increase in cost, and a control device including the device. And

In order to solve the above-described problem, the communication device of the present invention generates a communication packet (PK) based on data (D1) to be transmitted to a communication destination and performs communication with the communication destination (40 50), the first and second packets (P11, P12) are respectively generated from the data according to the first and second packet generation programs (PG1, PG2), and the first and second packets are generated according to the packet verification program (PG3). A processing unit (40) for collating whether or not the second packet has a predetermined relationship, and a communication unit (50) for transmitting the first packet as the communication packet according to the collation result of the processing unit. It is characterized by that.
According to the present invention, the first and second packets are respectively generated from the data to be transmitted to the communication destination according to the first and second packet generation programs, and the first and second packets are predetermined according to the packet verification program. Whether there is a relationship is collated, and the first packet is transmitted as a communication packet according to the result of the collation.
In the communication apparatus of the present invention, the communication unit includes a collator (51) that collates whether the first and second packets have the predetermined relationship, and the processing unit and the collation When both of the verification results of the device indicate that the first and second packets are in the predetermined relationship, the first packet is transmitted as the communication packet.
In the communication apparatus of the present invention, the first packet generation program generates the communication packet to be transmitted to a communication destination as the first packet, and the second packet generation program includes the first packet. Is a program that generates a complementary packet as the second packet.
In the communication apparatus of the present invention, the packet verification program and the verification unit calculate an exclusive OR of the first packet and the second packet, so that the first and second packets are preliminarily stored in the communication device. It is characterized by verifying whether or not it is in a predetermined relationship.
The control device of the present invention is a control device (2) that controls the field devices (1a to 1c), and first and second processors (21, 22) that generate packets to be transmitted to the field device. A control operation unit (20) including a collator (23) that collates packets generated by the first and second processors, and the communication device according to any one of the above, The communication unit provided in the communication device transmits a packet checked by the control calculation unit to the field device as the communication packet in addition to the communication packet generated based on data to be transmitted to a communication destination. It is characterized by doing.
Further, the communication device of the present invention detects and corrects an error that stores the first and second packets generated by the processing unit provided in the communication device and the packet collated by the control calculation unit. It is characterized by comprising a storage unit (30) capable of performing the above.

  According to the present invention, the first and second packets are respectively generated from the data to be transmitted to the communication destination according to the first and second packet generation programs, and the first and second packets are determined in advance according to the packet verification program. Since the first packet is transmitted as a communication packet in accordance with the result of this verification, the highly reliable communication can be realized without a significant cost increase. There is.

It is a block which shows the whole structure of the communication system with which the communication apparatus and control apparatus by one Embodiment of this invention are used. It is a block diagram which shows the principal part structure of the control apparatus by one Embodiment of this invention.

  Hereinafter, a communication device and a control device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a communication system in which a communication apparatus and a control apparatus according to an embodiment of the present invention are used. As shown in FIG. 1, the communication system CS includes field devices 1 a to 1 c, a control device 2, and a host management device 3, and various information can be communicated between the field devices 1 a to 1 c and the control device 2. It is.

  The field devices 1a to 1c are, for example, sensor devices such as flow meters and temperature sensors, valve devices such as flow control valves and on-off valves, actuator devices such as fans and motors, and other devices installed in plants and factories. It is connected to an IO communication network N1 that is a wired network. Operations of these field devices 1a to 1c are controlled based on control data transmitted from the control device 2 via the IO communication network N1. Further, the measurement data obtained by the field devices 1a to 1c are collected by the control device 2 via the IO communication network N1.

  The control device 2 is connected to the IO communication network N1, and controls the field devices 1a to 1c while communicating with the field devices 1a to 1c. Specifically, control of field devices connected to the IO communication network N1, collection of measurement data measured by the field devices connected to the IO communication network N1, and the like are performed. The control device 2 is also connected to the control communication network N2, and performs processing for determining whether or not a new field device is allowed to enter the IO communication network N1 under the management of the upper management device 3. Details of the control device 2 will be described later.

  The upper management apparatus 3 is connected to the control communication network N2, and gives various instructions to the control apparatus 2 for managing the communication system CS. The host management device 3 is realized by a desktop or notebook personal computer having an input device such as a keyboard and a display device such as a liquid crystal display device, and gives instructions according to operations performed by the administrator of the communication system CS. This is performed for the control device 2.

  Next, the control device 2 will be described in detail. FIG. 2 is a block diagram showing a main configuration of the control device according to the embodiment of the present invention. In FIG. 2, for simplification of illustration, a configuration for generating and transmitting communication packets transmitted toward the field devices 1a to 1c is illustrated, and other configurations are not illustrated. Yes.

  As shown in FIG. 2, the control device 2 of the present embodiment includes a control communication interface unit 10, a control calculation unit 20, a memory 30 (storage unit), an IO communication processing unit 40 (processing unit, communication device), and an IO communication interface. Unit 50 (communication unit, communication device), and generates a communication packet PK and transmits it to the field devices 1a to 1c. Here, the communication packet PK generated by the control device 2 includes data for arterial communication for the purpose of exchanging control data to the field devices 1a to 1c and data for diagnosis / prevention of the field devices 1a to 1c. Some are for venous communication for the purpose of communication. A communication packet for arterial communication is generated by the control calculation unit 20, and a communication packet for vein communication is generated by the IO communication processing unit 40 based on the data D <b> 1 transmitted from the upper management device 3.

  The control communication interface unit 10 includes a control communication controller 11 that controls communication performed via the control communication network N2, and transmits data to the control communication network N2 and is transmitted via the control communication network N2. Receive data. The control calculation unit 20 includes a control calculation processor 21 (first processor), a control calculation processor 22 (second processor), and a collator 23, and generates control data for the field devices 1a to 1c. And processing for packetizing the control data. The packet generated by the control calculation unit 20 is a communication packet for arterial communication to be transmitted to the field devices 1a to 1c.

  The control calculation processor 21 and the control calculation processor 22 operate in synchronization with each other and perform the same control calculation in parallel. That is, various processes such as the generation of the control data and the packetization of the control data are performed in parallel by both the control arithmetic processor 21 and the control arithmetic processor 22. The collator 23 collates one by one whether or not the calculation results of the control calculation processors 21 and 22 match. Here, since the packet is also generated by the calculation of the control calculation processors 21 and 22, the packet generated by the verification unit 23 is also verified.

  As described above, the control calculation unit 20 includes two redundant control calculation processors 21 and 22 and collates the calculation results with the collator 23, so that a packet (arterial system) is generated. Reliability of communication packets for communication) is ensured. Of the packets generated by the control arithmetic processors 21 and 22, the packet collated by the collator 23 when the contents match is stored in the memory 30 as the packet P1.

  The memory 30 is an ECC memory capable of detecting and correcting errors, and temporarily stores the packet P1 generated by the control arithmetic unit 20 and the packets P11 and P12 generated by the IO communication processing unit 40. Although not shown in FIG. 2, the memory 30 temporarily stores data D1 (data to be transmitted to the field devices 1a to 1c, which are communication destinations) transmitted from the upper management apparatus 3. An area to be used (buffer area) is also secured. By using an ECC memory for the memory 30, it is possible to detect and correct an error that occurs when the stored data is garbled or when the data is read or written, so that the reliability can be improved.

  The IO communication processing unit 40 is realized by, for example, one processor (the performance does not have to be as high as the control arithmetic processors 21 and 22), and generates and collates communication packets for venous communication, and for arterial communication. And transmission processing of communication packets for vein communication. Specifically, the IO communication processing unit 40 packetizes the data D1 transmitted from the upper management device 3 according to the packet generation program PG1 (first packet generation program) and the packet generation program PG2 (second packet generation program). A packet P11 (first packet) and a packet P12 (second packet) are generated. The packets P11 and P12 generated by the IO communication processing unit 40 are temporarily stored in the memory 30.

  Here, the packet generation program PG1 is a program that generates the original communication packet PK to be transmitted to the field devices 1a to 1c as the packet P11. On the other hand, the packet generation program PG2 is a program for generating a packet P12 complementary to the packet P11 generated according to the packet generation program PG1. That is, the packet P12 generated according to the packet generation program PG2 is a packet obtained by inverting the bit of the packet P11 generated according to the packet generation program PG1. These packet generation programs PG1 and PG2 operate in different contexts and different work areas.

  As described above, in addition to the packet P11 that is the original communication packet PK to be transmitted to the field devices 1a to 1c, the packet P12 is generated in software for the purpose of vein communication without significant cost increase. This is to improve the reliability of the communication packet. The packet P12 in which the packet P11 is bit-inverted is generated because of a failure of the data bus or the like (for example, a failure in which the logic of a specific bit is fixed at the “H (high)” level or the “L (low)” level. ) Is also possible. Further, unlike the control calculation unit 20, the IO communication processing unit 40 does not need to check the calculation results one by one and is intended to ensure the reliability of the packet, and therefore generates a packet in software. .

  Further, the IO communication processing unit 40 collates whether or not the packets P11 and P12 generated according to the packet generation programs PG1 and PG2 have a predetermined relationship according to the packet verification program PG3. Specifically, an exclusive OR (EXOR) for each bit of the packets P11 and P12 is calculated, and whether or not the calculation result for all bits is “1” (packets P11 and P12 are complementary). Check if there is.

  Further, according to the packet transmission program PG4, the IO communication processing unit 40 sends a transmission request of the packet P1 that is a communication packet for arterial communication and the packet P11 that is a communication packet for vein communication to the IO communication interface unit 50. Against. Specifically, for the packet P1 that is a communication packet for arterial communication, a transmission request is made to the IO communication interface unit 50 as it is. On the other hand, for the packet P11 which is a communication packet for vein communication, a transmission request for the packet P11 is made to the IO communication interface unit 50 in accordance with the result of matching performed according to the packet matching program PG3.

  That is, the IO communication processing unit 40 indicates that the result of the collation performed according to the packet collation program PG3 indicates that the contents of the packets P11 and P12 are in a predetermined relationship (the calculation result for all bits). Is “1”), a transmission request for the packet P11 is made to the IO communication interface unit 50. On the other hand, when the result of the above collation indicates that there is no predetermined relationship, the transmission request of the packet P11 to the IO communication interface unit 50 is not performed.

  The packet P1, which is a communication packet for arterial communication, is verified in the control calculation unit 20 and stored in the memory 30 which is an ECC memory, so that reliability is ensured. For this reason, the IO communication processing unit 40 outputs the packet P1 to the IO communication interface unit 50 as it is. On the other hand, although the packet P11 that is a communication packet for vein communication is stored in the memory 30 that is an ECC memory, the packet P11 is not verified and reliability is not ensured. For this reason, the IO communication processing unit 40 makes a transmission request for the packet P11 in accordance with the result of collation performed according to the packet collation program PG3.

  The IO communication interface unit 50 includes a collator 51 and an IO communication controller 52, and transmits a communication packet PK to the IO communication network N1 and receives a communication packet transmitted through the IO communication network N1. The collator 51 collates whether or not the packets P11 and P12 have a predetermined relationship when there is a transmission request for the packet P11 which is a communication packet for vein communication from the IO communication processing unit 40. Specifically, the collator 51 computes an exclusive OR for each bit of the packets P11 and P12, similarly to the collation performed in the IO communication processing unit 40 in accordance with the packet collation program PG3, and computes all bits. It is checked whether or not the result is “1”. The collator 51 does not perform collation when there is a transmission request for the packet P1, which is a communication packet for arterial communication, from the IO communication processing unit 40.

  The IO communication controller 52 controls communication performed via the IO communication network N1. Specifically, when there is a transmission request for the packet P1, which is a communication packet for arterial communication, from the IO communication processing unit 40, the packet P1 is transmitted as a communication packet PK to the IO communication network N1. On the other hand, when there is a transmission request for the packet P11 which is a communication packet for vein communication from the IO communication processing unit 40, the transmission control of the packet P11 to the IO communication network N1 according to the collation result of the collator 51. I do.

  That is, the IO communication controller 52 indicates that the collation result of the collator 51 indicates that the contents of the packets P11 and P12 are in a predetermined relationship (the calculation result for all bits is “1”). If there is, the packet P11 is transmitted to the IO communication network N1 as a communication packet PK. On the other hand, the IO communication controller 52 does not transmit the packet P11 to the IO communication network N1 when the above-described collation result indicates that there is no predetermined relationship.

  As described above, in the present embodiment, the packet P11 that is a communication packet for venous communication is the result of software verification performed by the IO communication processing unit 40 according to the packet verification program PG3, and the IO communication interface unit 50 Transmission control is performed according to the result of hardware verification performed by the verification unit 51. For this reason, the reliability of the packet P11, which is a communication packet for vein communication, is ensured similarly to the packet P1, which is a communication packet for arterial communication.

  Next, operation | movement of the control apparatus 2 in the said structure is demonstrated easily. In the following, an operation for generating a communication packet for arterial communication and transmitting it to the field device 1a, and an operation for generating a communication packet for vein communication and transmitting it to the field device 1a in order. explain.

[Operations when transmitting communication packets for arterial communication]
First, control data for the field device 1a is generated by each of the control calculation processors 21 and 22 provided in the control calculation unit 20, and packetization of the generated control data is performed in parallel. The packetized control data is collated by the collator 23. If the contents match, the generated packet is stored in the memory 30 as the packet P1.

  The packet P1 stored in the memory 30 is read to the IO communication processing unit 40 according to the packet transmission program PG4, and the IO communication processing unit 40 requests the IO communication interface unit 50 to transmit the packet P1. When a transmission request is made, the IO communication controller 52 provided in the IO communication interface unit 50 sends out the packet P1 requested to be transmitted to the IO communication network N1 as a communication packet PK. This communication packet PK is received by the field device 1a via the IO communication network N1.

[Operation when sending communication packet for vein communication]
First, data D1 to be transmitted to the field device 1a is transmitted from the upper management apparatus 3 to the control apparatus 2 via the control communication network N2. The data D1 is received by the control communication interface unit 10 of the control device 2 and then temporarily stored in a buffer area (not shown) secured in the memory 30.

  The data temporarily stored in the memory 30 is read out to the IO communication processing unit 40 and packetized according to each of the packet generation programs PG1 and PG2. As a result, an original packet P11 to be transmitted to the field device 1a and a packet P12 obtained by bit-inversion of the packet P11 are generated and stored in the memory 30. In addition, since an erroneous calculation may be performed in the IO communication processing unit 40, the packets P11 and P12 stored in the memory 30 are not necessarily in a complementary relationship.

  Next, the IO communication processing unit 40 reads the packets P11 and P12 from the memory 30, calculates the exclusive OR for each bit of the packets P11 and P12 according to the packet verification program PG3, and the calculation results for all the bits are obtained. It is checked whether or not it is “1”. Next, the IO communication processing unit 40 indicates that the result of the above collation indicates that the contents of the packets P11 and P12 are in a predetermined relationship (the calculation result for all bits is “1”). If there is, a request to transmit the packet P11 is made to the IO communication interface unit 50 according to the packet transmission program PG4. Note that if the result of the above collation indicates that there is no predetermined relationship, the transmission request of the packet P11 to the IO communication interface unit 50 is not performed.

  When a transmission request for the packet P11 is made from the IO communication processing unit 40, the collator 51 of the IO communication interface unit 50 calculates an exclusive OR for each bit of the packets P11 and P12, and calculates all the bits. It is checked whether or not the result is “1”. When the collation result by the collator 51 indicates that the calculation result for all the bits of the packets P11 and P12 is “1”, the IO communication controller 52 selects the packet P11 for which a transmission request has been made as the communication packet PK. To the IO communication network N1.

  The communication packet PK sent to the IO communication network N1 is received by the field device 1a via the IO communication network N1. When the comparison result of the comparator 51 indicates that the operation result for all bits is not “1” (the operation result of at least one bit is “0”), the IO The communication controller 52 does not send the communication packet PK to the IO communication network N1.

  As described above, in this embodiment, the IO communication processing unit 40 generates the packets P11 and P12 in software from the data D1 to be transmitted to the field devices 1a to 1c according to the packet generation programs PG1 and PG2, and the packet verification program PG3. Thus, it is verified by software whether the packets P11 and P12 have a preset relationship. For this reason, it is possible to improve the reliability of communication packets for vein communication without significantly increasing the cost.

  In this embodiment, in addition to the above-described software verification, hardware verification by the verification unit 51 is performed. In this way, by performing software verification and hardware verification in duplicate, it is possible to avoid erroneous output even if a failure occurs on one side. Packet reliability can be further increased. Note that the communication packet for arterial communication (packet P1) is collated by the collator 23 of the arithmetic control unit 20, so in this embodiment, the communication packet for arterial communication and the communication for vein communication are used. The reliability of both packets can be increased. As a result, reliable communication with the field devices 1a to 1c can be realized.

  The communication device and the control device according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention. For example, in the above embodiment, the example in which the control device 2 and the upper management device 3 are realized as separate devices has been described. However, the control device 2 and the upper management device 3 can be realized as one device.

  In the above embodiment, the control device 2 that controls the field devices 1a to 1c that perform communication via the IO communication network N1 that is a wired network has been described as an example. However, the present invention can also be applied to a control device that controls a field device (wireless field device) that performs communication via a wireless network.

DESCRIPTION OF SYMBOLS 1a-1c Field apparatus 2 Control apparatus 20 Control operation part 21,22 Control operation processor 23 Collator 30 Memory 40 IO communication processing part 50 IO communication interface part 51 Collator D1 Data P11, P12 Packet PG1, PG2 Packet generation program PG3 Packet verification program PK communication packet

Claims (5)

In a communication device that generates a communication packet based on data to be transmitted to a communication destination and communicates with the communication destination,
A processing unit for generating first and second packets from the data according to the first and second packet generation programs, and for verifying whether the first and second packets have a predetermined relationship according to the packet verification program; ,
A collator for collating whether or not the first and second packets are in the predetermined relationship, wherein both the processing unit and the collation result of the collator are the first and second packets A communication device comprising: a communication unit that transmits the first packet as the communication packet when it indicates that the relationship is predetermined . The first packet generation program is a program for generating the communication packet to be transmitted to a communication destination as the first packet,
The communication apparatus according to claim 1, wherein the second packet generation program is a program that generates a packet complementary to the first packet as the second packet. The packet verification program and the verification unit verify whether the first and second packets are in the predetermined relationship by calculating an exclusive OR of the first packet and the second packet. The communication device according to claim 2, wherein A control device for controlling field devices,
A control arithmetic unit comprising: first and second processors that generate packets to be transmitted to the field device; and a collator that collates packets generated by the first and second processors;
A communication device according to any one of claims 1 to 3 , and
The communication unit provided in the communication device transmits a packet checked by the control calculation unit to the field device as the communication packet in addition to the communication packet generated based on data to be transmitted to a communication destination. A control device characterized by: A storage unit capable of detecting and correcting an error for storing the first and second packets generated by the processing unit provided in the communication device and the packet checked by the control operation unit; The control device according to claim 4, characterized in that:

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